1------Homology------
- Two different species that I chose to describe homology were dragonfly and butterfly. Dragonflies have four long wings two on each side and butterflies have wide four wings two on each side. Dragonflies have long body shape like butterflies. It is easy to come up with an answer that dragonflies and butterflies share same trait of wings even though their wings look different.
- Dragonflies and butterflies share similar body shape but different shape of wings. Even though their wings seem different, they have common function, flying.
Dragonflies and butterflies share same ancestors from way back in centuries even when dinosaurs were existed and they also had wings to fly around to find food or run away from predators. In other words, the ancestors of these species share same trait and considered homologous.
2------Analogy-------
- Two different species that I chose to describe analogy were sharks and dolphins. They both live underwater, and also have fins that look alike. The sharks’ and dolphins’ appearances are very similar but inside of the body structure is very different. While shark use gills to collect oxygen underwater, dolphins go up to the surface to breath air. Their trait of fins seemed to be passed on from same ancestors but they are not.
- Dolphins and sharks have very similar body structure having streamed body shape and triangular fin on their back. The function of theses traits is to live underwater. But even though they have same function, since shark uses gills to collect oxygen, shark is considered as fish but dolphins are considered as mammals since they breathe atmospheric air.
Dolphins evolved from a land mammal with closest relative of hippo. Hippos don’t have any fins just like any mammals. That means whales and dolphins evolved their fins independently of sharks in different lineages. For the sharks, sharks are from fish ancestors, which lived underwater for centuries. However, the pectoral fins of sharks and dolphins are homologous. The dolphin’s pectoral fins evolved from the tetrapod hand, and tetrapod hand was evolved from pectoral fin of lobe-finned fish. Recent studies showed that lobe-finned fishes have the same number of bones as the pectoral fins of sharks which means that the front limbs of tetrapods evolved from the pectoral fins of the common ancestor of sharks, ray-finned and lobe-finned fishes.
I never really noticed the similarities of butterflies and dragonflies before, other than the fact that they both have flies in them. When you break it down though, the similarities are very apparent. Sharks and dolphins are definitely very similar. It's amazing how the similarities between them evolved even though they are very different species. Good work Eui!
ReplyDeleteGreat choice on the dragonfly and butterfly. Good research and discussion.
ReplyDeleteI have to admit I chuckled a little over your comment that shark ancestors have lived under water for "centuries". :-) To say the very least. Keep in mind that a century is only 100 years and sharks evolved about 450 million years ago. That is quite a few centuries!
I too never took into consideration the likeness of butterflies and dragonflies until you mentioned it in your first set of questions. I am curious as to what ancestor the butterfly and dragonfly had in common? I wasn't really aware that both of these organisms had been around since the time of dinosaurs. I think that dolphins and sharks might have been a little too similar of animals to choose for analogous traits but that's just my opinion. Other then their ancestors, it seems kind of difficult to differentiate between the two fin traits.
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